The present invention relates in general to respiratory equipment and, in particular, to a combination breathing bag and breathing tube for a closed circuit escape breathing apparatus, also referred to as a Self-Contained Self-Rescuer (SCSR), wherein exhaled carbon dioxide and water vapor flow through and react with a chemical in a chemical cartridge to yield oxygen gas to be inhaled by the user.
Closed circuit respirators or- SCSRs are known. The Portal-Pack(trademark) self-contained self-rescuer made by the Mine Safety Appliances Company (MSA) of Pittsburgh, Pa. (see MSA Data Sheet No. 01-01-17) is an example of such a device. Other examples of closed circuit respirators are disclosed in U.S. Pat. No. 5,267,558 to Haertle, et al. and U.S. Pat. No. 4,459,981 to Mascher et al.
The present invention provides an SCSR which incorporates numerous improvements to produce an SCSR which is smaller, lighter, easier to use and maintain and more reliable than known SCSR devices.
The present invention provides an improved breathing bag/breathing tube assembly which allows for several improvements over known SCSR devices. Such improvements include the operational advantage of having the breathing bag automatically unfolded through the act of the user donning the mouthpiece. The breathing bag/breathing tube assembly further provides for the elimination of parts such as a storage plug for the mouthpiece and a voice transmission device. The design of the breathing bag/breathing tube assembly provides for the mouthpiece to be disposed on the breathing bag. This design enables the vent valve of the bag to act as a plug in the mouthpiece when the bag is folded for storage. The combination breathing bag/breathing tube also provides for a height reduction versus most known SCSR devices. Voice communication by the user is improved and the need for any voice transmission device eliminated since the breathing bag/breathing tube assembly acts as speaking amplification diaphragm.
The firing mechanism for the oxygen emitting candle is also automatically activated when the bag is unfolded by the user. The combination breathing bag/breathing tube also incorporates a curved, pleated metal mesh acting as a foldable heat exchanger which insures that the breathing tube remains open with a controllable low flow resistance and a comfortable breathing air temperature.
The main housing of the SCSR of the present invention defines a receptor which allows the SCSR to be quickly attached to and removed from the user""s harness belt, thereby eliminating the cost and weight associated with fabric carrying pouches used in association with known SCSR devices. The projection which is received in the receptor to removably attach the SCSR to the harness belt is disposed on a mounting bracket which includes at least two means for removable mounting to a belt or a wall. A belt adaptor backing is also included for attaching the mounting bracket to various sizes of harness belts.
The SCSR of the present invention also utilizes a nose clip which requires only one hand to don or doff.
Other details and advantages of the present invention will become apparent from the following detailed description of the presently preferred embodiments of practicing the invention.